Carburetor



NOV. 7, 1944. K` R BLAKE 2,362,346

CARBURETOR Filed Feb. 23, 1952 2 Sheets-Sheet l A T ORNE) Nov. '7, 1944. K. R. BLAKE l 2,362,346

CARBURETOR Filed Feb. 23, 1932 2 sheets-sheet 2 IN V EN TOR.

Ken/70177 ,Q /a/re BY Q %kc ATTORNEY Patented Nov 7, 1944 CARBURETOR Kenneth R. Blake, Anderson, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., la corporation ol' Delaware Application February 23,1932, Serial No. 594,707

svclaims. (01.123-119) This invention relates to carburetors, and more particularly to a device for controlling the operation of the choke valve in a carburetor.

An object of the invention is to provide means responsive to temperature and other conditions for opening and closing the choke valve.

A further object of the invention is to provide a device responsive to temperature and engine speed and/or other factors for controlling the operationof the choke Valve.

Further objects and advantages of the invention will be apparent from thefollowing descript tion, taken inv connection with drawings, in which: l

Figure 1 is a diagrammatic view in elevation of a carburetor having connected thereto a choke the appended control embodying the invention;

Figure 2 is a similar view of a modified form of the invention;

preferably of the .unbalanced type, rotatably mounted on a shaft I6 disposed eccentrically of the air horn, so that air pressure on the outer face of the valve tends to open it.-

An operating lever I8 is fixed to shaft I6 and I has a pivotal connection with a link 20 which in turn is pivoted to one end of a lever 22, the other end of the lever being pivoted to a bracket 24, of any suitable construction, fixed to the engine frame by means not shown. Lever 22 passes through the slot of a slotted member 26 which is fixed to the free end of a thermally expansible member or bellows 28. The bellows is secured to bracket 24 and is connected by vtubing 30 to' a fitting 32 which is inserted in the water cooling system or disposed in any other position where it is subjected to the variable temperatures developed by the engine in its operation.

A link 34 is pivotally connected to lever 22 at one end and has its other end connected to a flexible diaphragm 36 which is mounted in a housing 38 supported by the bracket 24. The lower surface of the diaphragm is exposed to atmospheric pressure, and its upper face to the variable suction existing in the intake manifold, to which it is connected by a conduit 40. A compression spring 42 interposed between the housing 3 8 and lever 22 urges the vlever downwardly. This spring may be supplemented or substituted by a spring applied directly to shaft I6 in the known manner. In operation, assuming that the engine is at rest and cold, the choke valve will be maintained in its closed position by the torce of spring 42, bellows 28 being collapsed and diaphragm 36 being in its lowermost position. If now the starter is actuated to crank the car the manifold suction acting through conduit 40 is not sufllcient to raise diaphragm 36 substantially. and the differential of the air pressures acting on the opposite faces of valve I`4 will be suilicient merely to open the valve very slightly. When the engine begins to nre,- however, the manifold suction rises sharply, overcoming the force of spring 42 andI allowing the choke valve to open to a degree determined by the slotted member 26 contacting with lever 22. The bellows remains collapsed at this stage, however, setting an upper limit to the opening of the choke valve, which uctuates between closed and partially opened positions depending upon the speed of the engine.

As the engine warms up, the fitting 32 becomes warmer and expands the bellows, gradually lper mitting the choke valve to approach more nearly to its fully open position under the iniluence of manifold suction acting on diaphragm 36 and air pressure acting on the choke valve. If the engine is started while it is still warm from previous operation or due to externa1 weather conditions the action is the same except that the bellows permits the choke valve to open more fully, or completely, as soon as the engine fires. When the engine is hot, the bellows overcomes the force of spring 42 and maintains the choke valve nearly or completely open even during the cranking operation. A

The construction shown in Figure 2` is the same as that above described, except that the diaphragm 36 is substituted by the core 44 of a solenoid the winding of which is connected in the circuit 46 ofl the generator' 4,8I The operation is the same,'except that when the engine begins to re the generator-voltage rises sharplyso that core 44 exerts an upward force on lever 22 in the same manner as diaphragm 36. In this embodiment, the weight of core 44 takes the place of spring 42, although the spring may also be used if desired.

In the modiiication shown in Figures 3 and 4, the choke valve 50 is provided with an auxiliary flap valve 5I normally held closed by a spring -52, with the result that a comparatively 'small pressure diierential between the opposite faces of the choke valve will cause some air to be admitted to the carburetor. The thermostatic control of the choke valve consists oi a bellows 54 supported by means of a bracket 56 and Vhaving a' fitting 58 disposed in the cooling system or in any position where itis subjected to variable temperatures developed by the engine. The connection between the bellows and choke comprises a lever 6.0 xed to the -shaft B2 of the choke and having a pin-and-slot connection with a rod B4 the upper end of which is reciprocable within a sleeve 66 secured to the bellows. A compression spring 68 is positioned between ilanges on the rod 64 and sleeve 66 to provide a yielding connection. The operation of this modification will be apparent from the above description.

Although the invention has been described with particular reference to certain specic embodiments thereof, it may be embodied in other forms, and is not limited except by the terms of the following claims.

I claim:

1. In combination with a carburetor for an internal combustion engine having a choke valve,` and with the generator circuit of the engine of means actuated by said circuit for operating the choke valve, and means controlled by engine temperature for modifying the operation of the choke valve independently of said rst mentioned means.

trol means for the choke valve comprising a ther- 4. In combination with a carburetor having en 1 unbalanced pressure responsive choke valve, control means for the choke valve comprising a thermostat and a pressure sensitive diaphragml both connected to said valve by unyielding connections and simultaneously eective under predetermined conditions of engine operation to move said valve toward open position.

5. A combination as dened in claim 4, wherein the thermostat is connected to the choke valve by a lost motion connection,

6. A device for controlling the air inlet ot a carburetor associated with an internal combustion engine, comprising an air inlet valve responsive to suction within the carburetor, a flexible diaphragm responsive to suction posterior to the carburetor, and means responsive to temperature remote from the carburetor connected to fthe air valve by an unyielding overrunning connection, the valve, diaphragm, and temperature responsive means being simultaneously operative during the operation of said device. l

7. In combination with a carburetor for an internal combustion engine provided with a generator circuit, a pressure responsive air inlet valve in the carburetor, means energized by said circuit for biasing the choke valve toward open position, and means controlled by engine temperature' for iniuencing the operation of the choke valve independently of said rst mentioned means.

8. In combination. with an internal combustion engine having a generator circuit, a carburetor having a choke valve responsive to suction within the carburetor, yielding means urging the choke valve toward closed position, electrical means energized by the generator circuit for yieldingly urging the choke valve toward open position, and a thermostat controlled by temperatures developed by the engine in its operation for influencing the operation of the choke valve independently of said electrical means.

KENNETH R.. BLAKE. 

